Apparatus for making electrical coils



V. G. APPLE APPARATUS FOR MAKING ELECTRICAL COILS Ongmal Flled Nov 20, 1930 5x ecufars {Edward l Gear/6y Darrow l W 6%415 July 3, 1934.

Patented July 1934 UNITED STATES PATENT OFFICE APPARATUS FORCMAKING ELECTRICAL ILS Vincent G. Apple, deceased, late of Dayton, Ohio, by Herbert F. Apple, Edward M. Apple, and Gourley Darroch, executors, Dayton, Ohio 3 Claims.

This invention is a division of a copending application Serial No. 496,847, filed November 20th, 1930, now Patent No. 1,893,262, Jan. 3, 1933, and relates to apparatus for making electrical coils which comprise a fabric reinforced exterior covering of hard infusible and insoluble insulating material, which renders them substantially indestructible even when subjected to severe usage.

The object of the invention is to provide apparatus for making such a coil and applying the covering thereto.

This object is attained in the apparatus hereinafter described and shown in the accompanying drawing wherein,

Fig. lis an axial section through the winding spool of the apparatus as it appears when ready to have a coil wound upon it.

Fig. 2 is a special washer which is part of the winding spool shown in Fig. 1.

Fig. 3 shows the spool with the winding in place,

Fig. 4 shows the spool after the several finishing turns have been wound.

Fig. 5 is a spring ring used for accurately forming the outside of the coil. I

Fig. 6 is a tool used to apply the ring shown in Fig. 5 to the coil.

Fig. '7 is a spacing fork used to determine the thickness of the coil.

Fig. 8 is an axial section through a coil and its spool when the structure is ready to be baked.

Fig. 9 shows a completed coil.

Similar numerals refer to similar parts throughout the several views. 7 35 In the copending applications Serial No. 356,-

586, filed April 19th, 1929; now Patent No. 1,887,- 005, Nov. 8, 1932; Serial No. 430,864, filed February 24th, 1930 now Patent No. 1,845,116, Feb. 16, 1932; and Serial No. 455,296, filed May 24th, 1930, now Patent No. 1,826,297, Oct. 6, 1931 is disclosed a procedure whereby liquid insulation is deposited in a relatively thick layer around a wire while the wire is uncoiled, then dried just enough to prevent its being pressed out from between the I turns when it is being wound into coils, but not heated enough to convert it into the insoluble and infusible state until after it is wound into the coils.

This method of applying liquid insulation to the individual turns of a coil may be substantially followed in the present invention, and while there are now available a number of liquid insulating materials which have the necessary insulating qualities as well as the requisite cementing properties, and which will harden by the application of heat to an insoluble and infusible state, the insulating material selected from those available must be determined with regard to the use to which the coils are to be put, some of the insulating materials being especially resistant to one thing and some to another.

It is well known that, of all the sheet insulating materials available, those having the highest tensile strength and which will stand the greatest physical abuse are made by thoroughly saturating a sheet of loosely woven cloth or canvas with liquid insulation and compressing it to a thinner section and curing out the insulation.

The process for which the present apparatus is applicable contemplates selecting a suitable liquid insulation, placing a considerable layer of it around each individual turn of the coil, forming a covering of insulation-impregnated non-metallic fabric completely around the outside of the coil, and, while holding it to a definite size, converting the insulation into an insoluble and infusible state in which the insulation surrounding the wires and that in the meshes of the fabric has been fused together into one continuous mass from which stranded coil terminals emerge. The so apparatus here shown does not include means for coating the individual turns of the wire, that being preferably done by means of the apparatus shown and. claimed in my copending application, Serial No. 356,586, filed April 19th, 1929.

In the drawing a stud 11 has a head 12, and is threaded on the end 13 for nut 14. Washers 16 and 17 are slidably fitted to stud 11 while a third washer 18 is held against the shoulder 19 by nut 14. Washer 18 has a shallow annular groove 21 in the inner face. Washer 17 is shown in detail in Fig. 2 and has a shallow groove extending through the edge of the central opening 22 as at 23 thence radially outward in the face of the washer as at 24. The end 26 of the stud 11 is adapted to be held in a revolving chuck or other device, not shown, to rotate the spool when the coil is being wound.

A length of loosely woven sleeving 27' of nonmetallic fabric of a size sufficient to fill the grooves 24 and 23 in washer 17 and as much longer as is required to make enough turns around the stud 11 to cover it, is provided. This s1eeving is thoroughly impregnated with suitable liquid insulation, except that portion which lies in the 106 grooves 24 and 23. The liquid insulation absorbed by the sleeving 27 is dried sufiiciently to expel the greater part of the solvent so that it may conveniently be handled. The washers 28 are cut from thick loosely woven cloth which has 110 been heavily impregnated with the liquid insulation, the fabric compressed and dried, not enough to bring about the reaction which converts the insulation into an infusible solid but just enough to make it sufficiently stiff to hold its shape while the coil is being wound.

The spool in condition to have the wire wound upon it is shown in Fig. 1, but the order in which the several parts of the spool are thus assembled may preferably be described. To assemble the spool as shown in Fig. 1 the end 26 is preferably held in the chuck of the winding spindle, the washer 16 put on the stud 11, a length of stranded terminal wire 29, slightly longer than the sleeving 27 is joined to the end of the insulated wire 31, the terminal wire 29 threaded through the sleeving 27, the terminal wire and sleeving through the opening 22 of washer 1'7 and laid in grooves 23 and 24, the washer 17 placed on stud 11, two washers 28 put on, and the washer 18 secured to the stud 11 by the nut 14. After assembly as shown in Fig. 1 the coil may be wound, care being taken that the sleeving 27 is so wound as to completely cover the stud 11 thus forming the inner layer of the coil.

The wire 31 is .preferably of copper and preferably of the kind having a cotton or other porous covering which has been impregnated and coated with liquid insulation and dried as described in the copending applications hereinbefore referred to, and when the proper number of turns have been wound on the spool the wire 31 is cut off and a length of stranded terminal wire 32 joined to it. Another length of sleeving 33 is placed over the terminal wire 32 as shown in Fig. 3. This length of sleeving has, like sleeving 27 been thoroughly impregnated in the liquid insulation and dried. The sleeving 33 is of sufficient length to compose the outer layer of the coil, but before it is wound on the coil the washers 28 are preferably turned inward as at 34, Fig. 4. The outer layer of the coil is then formed of the several turns of the sleeving 33 wound over the inturned edges 34 of the washers 28, the end of the sleeve being preferably inserted under the last round and drawn up taut.

When a coil has been wound as shown in Fig. 4 with the inner and outer layers covered with insulation treated fabric sleeving and the sides covered with insulation treated fabric washers the coverings are preferably compressed slightly to make them more dense and to make the coil more accurate as to size. To so compress the coverings I provide the several tools shown in Figs. 5, 6 and 7.

The spring ring 36, Fig. 5 has an inner diameter equal to the outer diameter of the finished coil when the ends 37 of the ring are brought together. Half holes 38 are provided in the ends 37 to clear the sleeving 27 and 33. The width of the ring 36 is equal to the Width of the space between the washers 16 and 18, Fig. 4.

The clamp 39, Fig. 6 is made in two main parts hinged at 41. The opening 42 is equal to the outside diameter of the ring 36 when handles 43 are still spaced apart as at 44. The spacer 46, Fig. 7, comprises a handle 47 and the forked ends 48, the opening 49 between the forked ends being slightly larger than the stud '11.

To compress the coverings tightly up to the coil Fig. 4, the ring 36 is first sprung over the washer 18 with the sleeving 27 and 33 coming out between the ends 37 of the ring. The clamp 39 is then placed around the ring with the ends 37 of the ring corresponding to the opening 44 between handles 43. The handles 43 are pressed together until the ends 37 come together with the sleeving 27 and 33 emanating from the half holes 38. The ring 36 now closely surrounds the washer 17 at one edge and at the other is in alignment with the annular groove 21. The washer 16 being loose on stud 11 is now forced by a suitable press toward the washer 18 to compress the fabric washers 28 sidewise against the coil and to enter the edge of the ring 36 in the annular groove 21. When the edge of the ring 36 has been forced to the bottom of the annular groove 21 there will be just enough space between the head 12 and the washer 16 to permit the ends 48 of the tool 46 to be inserted. After insertion of the ends 48 under the head 12 the clamp 39 may be removed and the coil remains under pressure within the enclosing spool, but while the procedure comprising a reduction of the dimensions of the coil coverings to make them more dense and to more firmly unite them with the turns of the wire is much preferred, a process omitting the step but otherwise following the procedure outlined is considered within the spirit of the invention.

Fig. 8 shows a coil on the spool with the ring 36 holding the diameter of the coil to size and the ends 48 of the spacer 46 holding the coil under axial pressure. In this condition the coil is baked to bring about the final reaction of the insulating material whereby the insulation between the individual turns of the wire and the insulation carried by the fabric covering is first fused together into a single mass then by further heating converted into an insoluble and infusible state. The baking is preferably kept at a low heat for a con siderable period of time inasmuch as a too rapid baking tends to generate gas within the coil and drive the insulation to the surface, but with proper regulation of the baking temperature just enough of the insulating material is brought to the outside to make the fabric covering on the coil a smooth surface.

When reaction of the insulating material is complete the coil may be removed from the spool. This is preferably done by a series of steps comprising removing the nut 14, holding the washer 18 under the edge 51 and by pressing on the end 13 removing the washer, then by holding under the edge 52 of washer 16 again pressing on the end 13 and removing the stud 11. The ring 36 is now removed after which the sleeving covered terminal 29 is raised out of the groove 24 in washer 17 whereupon washer 17 is readily removed. The completed coil now appears as at 53, Fig. 9 where terminal wires 29 and 32 emerge from a fabric reinforced insulation covered coil through th sleeving 27 and 33 respectively.

It will be seen that both the coil and the method in which it is made differs radically from the conventional methods. Coils made by conventional methods are wound on a mandrel from which they must be removed in order to impregnate them, either by dipping them in liquid insulation or by enclosing a number of them in a pressure-tight tank of the liquid and forcing the liquid into the wound coils. When these conventional methods are employed the coils may not be thoroughly impregnated unless they were removed from the mandrel and when so removed before impregnation the several turns must be insulation because of the quantity of the liquid too which would completely cover the mandrel and be baked upon it, such covering requiring much time to remove, and because the terminal ends of the coils would be cemented so thoroughly to the mandrel as to defy removal of the terminal ends.

Coils made by conventional methods then must be removed from the mandrel before impregnating, they must be tied or taped, they do not have the conductive portion of their several turns spaced apart by a great enough amount of the liquid insulation and they lose a considerable part of that which is gotten between the conductive portion of their turns when the coils are baked, they do not hold a definite size or shape, and they do not have adequate protection on the outside against entry of foreign matter or against physical abuse.

The coil herein shown and described has a greater amount of the insulation mass separating the conductive portion of the several turns and an impervious covering of fabric reinforced insulation entirely surrounding the turns, it is extremely accurate as to size and shape, it is wound on and completed on the same winding spool without loss of material and without get ting any appreciable quantity of the cementitious insulation on the winding spool itself, and no taping or tying operation is required in the process of making.

Believing that these advantages are both new and useful,

The claims are,

1. For winding an electrical coil and compressing it axially after it is wound, apparatus comprising in combination, a center stud, a head at one end of said stud, a washer fixed against axial movement on the other end of said stud, an axially movable washer on said stud between said head and said fixed washer and a spacing member adapted to be inserted between said head and said movable washer after said coil is wound.

2. For winding an electrical coil and compressing it axially after it is wound, apparatus comprising, in combination, a center stud, a head at one end of said stud, a washer fixed against axial movement at the other end of said stud, two washers having central openings slidably fitted to said stud situated between said head and said fixed washer, the slidable washer nearest said fixed washer having a shallow groove extending axially through its central opening thence outwardly through the edge adjacent the other slidable washer, and a spacing member adapted to be inserted between said head and the nearest slidable washer after said coil is wound.

3. For winding an electrical coil, decreasing its dimensions after it is wound and baking it while so decreased, apparatus comprising, in combination, a center stud, a head at one end of said stud, a fixed washer somewhat larger in diameter than the coil having an annular groove of substantially the diameter of the coil in the side facing said head, two washers having central openings slidably fitted to said stud situated between said head and said fixed washer, the slidable washer nearest said head being somewhat larger than the coil and the slidable washer nearest said fixed washer being substantially the diameter of the coil and having a shallow groove extending axially through its central opening thence outwardly through the edge adjacent the other slidable washer, a split ring adapted to surround the coil and be brought together closely around the smaller slidable washer and entered into the annular groove of the fixed washer, a clamp for bringing together said split ring, and spacing means adapted to be inserted between said head and the larger slidable washer to hold said split ring in said annular groove.

HERBERT F. APPLE,

EDWARD M. APPLE,

GOURLEY DARROCH, Ezecutors for Vincent G. Apple, Deceased. 

